1. Field
The disclosed and claimed concept relates generally to electrical power distribution equipment and, more particularly, to a triggered arc flash arrester.
2. Related Art
Electrical power distribution equipment is generally understood in the relevant art and includes, among other devices, circuit interrupters and other equipment that can interrupt the delivery of current to a protected portion of a circuit. Such power distribution equipment typically also includes switchgear that often comprises electrical busways, electrical disconnects, fuses, and other devices which are located inside a metal enclosure that is connected to electrical ground and which are configured to enable the disconnection of electrical equipment. Such equipment is generally well suited to interrupt the flow of current to a protected portion of a circuit during certain predefined overcurrent conditions, under-voltage conditions, and other conditions. While such equipment has been generally effective for its intended purposes, it has not been without limitation.
For instance, multi-phase AC electrical distribution equipment can sometimes be subject to arcing faults between phases, and such arcing faults can occur at various locations within switchgear cabinets, such as between power buses, or between a power bus and a grounded metal component, by way of example. Such arcing faults can result from tools, animals, water, or other foreign materials becoming situated between a pair of different electrical phases or between an electrical phase and a grounded metal component. Such arcing faults can produce high energy gases which can be extremely dangerous to equipment and nearby personnel. It thus has been known to provide triggered arc flash arresters that include a pair of spaced conductors within an evacuated envelope and that are structured to be triggered to change state in one fashion or another. Upon such a change in state, the triggered arc flash arrester can support an arc between the spaced conductors for a short period of time to commutate the arcing fault into the vacuum vessel and enable an upstream circuit interrupter to interrupt the power that is feeding the arc fault. Triggered arc flash arresters and switchgear systems that include the same are described generally in U.S. patent application Ser. No. 13/296,765 filed Nov. 16, 20111, the disclosures of which are incorporated herein by reference.
Such triggered arc fault arresters can be electrically connected with a plurality of AC phases in any of a variety of fashions. For instance, the triggered arc flash arrester(s) can be electrically connected between electrical phases wherein, for instance, one conductor of a first triggered arc flash arrester is connected with phase A (φA ) and another conductor of the first triggered arc flash arrester is connected with phase B (φB). Likewise, one conductor of a second triggered arc flash arrester can be connected with φB, and another conductor of the second triggered arc flash arrester can be connected to phase C (φC). Alternatively, each phase may be electrically connected with a conductor of a separate triggered arc flash arrester, with the opposite conductors of each such triggered arc flash arrester being electrically connected together. Still alternatively, the opposite conductors that are electrically connected together can additionally be grounded.
While such triggered arc flash arresters have been generally effective for their intended purposes, they have not been without limitation. As is generally understood in the relevant art, such triggered arc flash arresters maintain an electrical arc between spaced conductors for a short time in order to enable, by way of example, an upstream circuit interrupter to interrupt the current feeding an arcing fault. However, the arc that has been triggered within the triggered arc flash arrester can be extremely powerful and can have a deleterious effect on the evacuated envelope. It thus would be desirable to provide an improved triggered arc flash arrester.